The present invention relates to the field of rack mounted telecommunication devices, and in particular to a device having front access jacks distal of the device face.
Electronic devices are often rack mounted, with a typical rack being 19″ wide. A device designed for a standardized size rack having standardized input and output plugs or jacks is often referred to as a module. The height of a module is often defined in terms of multiples of a unit height, with 1 unit height being 1.75″ or 44.45 mm.
Midspan equipment in a local area network, such as an IEEE 802.3 compliant Ethernet network, supplies added functionality to the local area network. Midspan equipment is typically supplied in a rack mounted module connected between the data circuit terminating equipment (DCE) module and the data terminating equipment (DTE). In one embodiment, such as that described in the IEEE 802.3af standard, midspan equipment is used to supply power to the DTE over the communication cabling.
In a typical 10 Base-T, 100. Base-T or 1000. Base-T based system, 4 sets of twisted wire pairs are used to connect each jack of the DCE to a DTE. Typically, the 4 sets of twisted wire pairs are terminated at each end in a single standardized connector, such as an RJ-45 connector. Alternatively, at the DCE end a Telco or CHAMP connector, available from Tyco Electronics, is used to gang multiple output ports on a single connector. In many installations cabling infrastructure is laid down prior to installation of any DCE and DTE. This is typically accomplished via a patch panel, with cabling from the intended DTE location being connected to a 110 punch down or Krone connection at the back of the patch panel. The front face of the patch panel presents a front side connection for each intended DTE location.
Connections in a telecommunication rack for which changes may need to be made during normal operations are typically supplied at the face of the modules, as access to the rear of the telecommunications rack is often difficult. Rear connections are normally reserved for power and data communications backbone connections, as these are not typically disturbed once the initial setup has been completed. In particular, in a typical communication rack assembly, cables for which changes may be made during normal operations are dressed in the front of the rack and cables for which changes are not normally made are dressed in the back of the rack.
For an application in which midspan equipment is utilized, each port of the DCE for which the midspan equipment is to provide functionality must be connected to the midspan equipment, and an output port from the midspan equipment for connection to the DTE must be supplied. Thus, the physical size of a midspan equipment module is at least a function of the number of input and output ports required.
Preferably, a rack mounted midspan equipment module should take up a minimum amount of rack space, and at the same time support a maximum number of input and output ports. As indicated above, for each port for which midspan functionality is supplied, ports for connection to both a DCE and a DTE must be supplied. A ganged housing of 12 RJ-45 jacks designed to fit into a 1 U height module is commercially available, comprising 6 pairs of vertically stacked RJ-45 jacks. Typically, a single RJ-45 jack is associated with a single port. Unfortunately, the maximum number of RJ-45 jacks which can be placed in the front panel of a 1 U height module of a standard 19″ rack is no more than 56. Since for each port there is a corresponding output port, the maximum number of combined input and output ports supportable in a midspan device of the prior art is 28.
There is therefore a need for a device configuration which enables high density front access, and in particular a need for a configuration for a high density front access rack mounted module.